The U.S. House of Representatives on Wednesday urged China to stop censoring news about the Tiananmen Square crackdown as authorities enforced a tight blackout ahead of the 25th anniversary.

In a nearly unanimous vote, the House of Representatives approved a resolution that called on China “to stop censoring information about the Tiananmen Square massacre.”

It urged the country to “end the harassment, detention, torture and imprisonment of Chinese citizens expressing their legitimate freedom of religion, expression and association, including on the Internet.”

Representative Nancy Pelosi, the House leader of President Barack Obama’s Democratic Party, brought onto the floor a framed copy — signed by exiled dissidents — of the famous picture of the man who stood alone on June 5, 1989 to hinder a column of tanks at the square in central Beijing.

“It’s one of the most iconic figures in the history of democratic freedoms in the world. However, if you were to go to China and ask young people about this picture, they know nothing about it,” Pelosi said.

“The heroes — we have to talk about them, because the Chinese tell them, ‘Nobody cares about you anymore,'” said the former House speaker, who angered Beijing authorities in 1991 by unfurling a banner in Tiananmen Square in memory of dead demonstrators.

The crackdown killed hundreds of people — by some estimates, more than 1,000. China censors any mention of the Tiananmen Square crackdown, with many young people having no knowledge of it, and has ramped up already strict controls ahead of the 25th anniversary.

Representative Chris Smith, a Republican who spearheaded the resolution, said that Tiananmen Square “has come to symbolize the brutal lengths China’s Communist Party will go to remain in power.”

“We will never forget Tiananmen as long as the Chinese people cannot discuss its significance openly without harassment or arrest,” Smith said.

Despite the latest resolution, the United States and other Western countries resumed full relations with China within years of the crackdown as businesses clamored to enter the world’s most populous nation.